My approach to learning is to split time between learning something new (85%) and practice something you just finished learning.
I cannot express how important practice is. You’d be surprised how quickly things are forgotten.
Practice gives things time to settle into the crevices of your brain. You will REALLY understand the things you thought you already understood.
Practice helps with “muscle memory” so you automatically know the syntax of how to write a function, for example. More “muscle memory” means less cognitive load on your brain to learn new things.
So by all means keep adding new stuff but take 5 or 10 or 20 minutes everyday to practice older skills (not forever but at least until it feels more “baked in”).
Also - it’s important to me to keep switching between learning via videos, tutorials etc and learning via projects that I care about. They are both useful in keeping the motivation level up.
Hope that helps.
I will say that I learned most about HTML and CSS by actually doing the projects, so that may benefit me more.
It seems that you’re more the learning-by-doing type so maybe completing more personal projects is the way to go.
You can always come back to FCC if you feel like you want to rest from projects for awhile, and do structured learning instead.